@article{GDZPPN002185482,
title = {The stability of bases in Banach and Hilbert spaces.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {247},
year = {1971},
pages = {136-146},
zbl = {0207.12101},
url = {http://dml.mathdoc.fr/item/GDZPPN002185482}
}
Holub, J.R.; Retherford, J.R. The stability of bases in Banach and Hilbert spaces.. Journal für die reine und angewandte Mathematik, Tome 247 (1971) pp. 136-146. http://gdmltest.u-ga.fr/item/GDZPPN002185482/